Process for cleaning contact material



T. L. BRIGGS.

PROCESS FOR CLEANING CONTACT MATERIAL. APPLICATION FILED SEPT. 15, 1920.

1,429,g92,, Patented Sept. 19, 1922.-

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@ROCESS FQR CLEANING- CON'IAC'I MATERIAL.

Application filed eptember 15, 1920, Serial No. 410,547.

To all whom it may concem:

Be it known that I, 'IHoMAs LYm oN Emcee, a subject of the Kin of Great Britain, and a resident of F lus ing, Long Island, State of New York, have invented certain new and useful Improvements in Processes for Cleaning Contact Material, of which the following 'is'a specification.

This invention has ,reference to 'a method of removing from contact substances mounted on fibrous material the foreign substances that commonly collect thereupon; and relates particularly to a method of removing such foreign substances from platinized asbestos after the latter has been employed in the production of sulfuric anhydride, and accomplishing this result without removal (of the contact material from the contact chamber, while leaving the contact material at :the end of the operation-in position and condition to operate effectively.

Two general methods have heretofore been employed for regenerating contact" materials, each having been varied in numerous Ways as to details, but the basic theories of operation having remained unchanged. In

all of the variations of one of-these general methods, the contact material is removed in its entirety from the converter, and is returned to the converter after treatment; when platinized asbestos is dealt with, the platinum is completely, dissolved andseparated from both obstructive and non-ob- 'structive substances, and must then be redeposi'ted upon fresh asbestos, while the used asbestos carrier is destroyed or rendered un fit for further use. In tga other general method of regeneration, in which the contact material is treated in place and the contact carrier. is not destr'o'yed, only such'obstructivesubstances as can be converted into volatile matter, and the non-obstructive substances (i. e., contact poisons), are removed by volatilization by passing'a gas or a mixture of gases through the contact mass.

Inno process with which I am familiar that has heretofore been employed for cleaning contact substances is a material introduced into the converter for the removal, by solution or washing, of foreign substances from the contact mass, and in this respect the process described herein is believed to be a marked improvement over the prior art, since it possesses, among others, the following advantages :(a)- the contact mass is not removed from the contact chambers,.but is cleanedin place-by solution of the watersoluble foreign substances, without necessitating material or substantial ,disarrangement of either the contact carrier or the con-- tact substance; (6) both obstructive I and non-obstructive substances are removed by solution, accompanied bypart, if not all, of the water-insoluble substances; (0) neither the contact substance nor the contact carrier seems tobe affected chemically, and neither seems to be affected physically except as regards removal of the foreign substances; (d) the apparatus necessary for carrying out my improved process may be installed quickly and at very little expense,

and need occupy very little space; (e) since neither gas nor chemicals are required (only Water being used), since both the original contact substance and the original contact carrier remain in place and are available for further use, and since the process requires less time than any of the processes heretofore'employed, thereby limiting the length of time that the converter must be out of use whilebeing cleaned, the saving in expense accomplished by my invention is obvious.

' My method of cleaning the contact material comprises washing ity in situ by means of water, without disarranging the contact material. In carrying out, this method in actual practice, the contact chamber is first allowed to cool, after which plain water, at

ordinary temperature, is caused to flow into the chamber, from the bottom upwards, its rate of inflow being so regulated as to be rapid enough to promote solution of the water-soluble foreign matter, without permanently displacing the contact material, or permanently disarranging either the contact substance or the contact carrier. I have found in practice that, when working with a contact chamber of the Herreshofi' type (such- ,as disclosed in U. S. Patent No. 719,333),

with an internal diameter of seven feet, and

containing fifty plates, spaced an inch apart,

and each carrying contact material occupying say one-half to three-quarters of the open space between the plates, the rate of inflow of the water may be as great as ten vertical inches an hour. When the chamber is full, the water supply at the bottom is shut off, and warm water (preferably at 90-100 F.) is run in at the top of the chamber at approximately the same rate at which the inflow at the bottom was regulated, an outflow meanwhile being provided for at the bottom at the same rate as that of the inflow at the .top. When the water leaving the bottom of the chamber shows, upon test, that it no longer carries either dissolved or insoluble foreign matter, the water inflow furic anhydride commercially, until the contact material is thoroughly dry, and the temperature of the chamber has been raised to approximately that usual in contact operation, say 450 C. The apparatus is then readyior resumption of contact operation.

-Wh1le my improved process may be carried out successfully irrespective ofthe relative temperatures of the water already in the chamber and that subsequently. inducted at the top, I have found that much better results are secured if the water supplied at the top is-somewhat warmer than that ale ready in the chamber.

As a typical illustration of the commercial application of my present invention, T have selected its use in regenerating platinized asbestos, such as is commonly employed as a contact material in the catalytic production of sulfuric anhydride, and have illustrated apparatus adapted for carrying out the process, in the accompanying drawings, in

which Fig. 1 is a view in side elevation of the complete apparatus, attached to a contact chamber;

Fig. 2 is a top plan view of a suspended disk arranged in the cover for the contact chamber;

Fig. 3 is an enlarged detail view, in elevation, of portions of the contact mass and the supporting plates therefor.

n the drawings, 4 indicates a contact chamberof the ordinary type, having supported within the shell thereof a plurality of equidistant, horizontally-disposed plates 5,' commonly spaced about an inch apart, each of which is provided with a plurality of perforations 6, and supports a layer of the contact mass 7 which preferably occupies approximately one-half to two-thirds of the space between each two of the superposed plates. In Fig. 1 the approximate positions of the top and bottom plates only are indicated.

Water at ordinary temperature is supplied to a gravity tank 8 through a pipe 9 fitted preferably by op aaaaaaa with a valve 10, its delivery into the tank being controlled automatically by an ordinary float valve 11, and the bottom of the tank being above the level of the top of the contact chamber. From the tank 8, the water passes by gravity through a pipe 12 into a larger pipe 13, thence through a pipe 14: of approxlmately the samesize as pipe 12, and through a smaller pipe 15, fitted with a valve 16, into a ipe 17 which is considerably larger than pipe 12, has open communication with the contact chamber through the bottom thereof, and is fitted with a gate valve 18 located below the connection with pipe 15. Pipe 13 is extended upward at 19' to afl'ord an escape for entrained air in the pipes, and a glass tube gauge 20 is connected with pipe 17, above the connection of the latter with pipe 15, by a pipe 21 fitted with a valve 22. Below gate valve 18, pipe 17 has a gravity connection, by means of pipes 23 and 24, the latter having a valve 25, wlth a filter, tank 26, having cloth sheeting or other filter material 27 therein, and fitted with a drain pipe 28 having a valve 29. The function of the filter is to catch and save any useful solids that may have been carried off.

v The warm water inlet to the contact chamber is at the topthereot, the water being supplied from any suitable source, preferably by gravity, through a pipe 30 fitted with a'valve 31. A circular disk 34, of wood or other suitable material, is suspended from cross bar 35 by means of a wire, (said cross bar resting upon the usual flange 32 of the converter chamber) so as to rest upon the surface of the water-body. It serves to break the fall of the water and to spread it at the surface so as to reduce or avoid agitation.

To carry out my present invention with the apparatus just described, the first step is to suspend the contact operation, and to permit the contact chamber to become cooled,

to a temperature of approximately Gate valve 18 in pipe 17 is then closed tightly, valve 22 in pipe 21 is opened to afito'rd access from said pipe to the glass tube'gauge 20, and water at ordinary temperatureiis admitted to gravity tank 8 ening valve 10 in pipe 9. The rate of admlssion of the water to pipe 17, and thence to the contact chamber, is regulated by means of valve 16 in pipe 15, its rate of rise in the contact chamber being indicated by the gauge 20, and its rate of inflow being kept slow enough so that none of the contact mass is harmfully disarranged thereby, while at the same time being fast enough so that the process is-not prolonged unnecessarily. It will be noted that the use of the small reducing pipe 15 for admitting the water into the larger pipe 17, facilitates regulating the rate of rise in the contact chamher, without the necessity for extremely careful manipulation of the valve 16.

When the contact chamber has been filled with water at ordinary temperature, in the manner just described, valve 16 is closed, to prevent further'fiow of water from pipe 15 into pipe 17 during the discharge of water from the chamber, valve 31 is opened to permit Warmer water (preferably at 90 to 100 F.) to flow through'pipe 30 into the chamber, valve 18 is opened, to permit water from the chamber to flow into pipes 23 and 24, and valve 25 is opened to permit the water thus drawn off from the chamber to be discharged into the filter tank 26, valves 31 and 25 being so adjusted that the rate at, which the water passes therethrough-will be substantially the same inboth, and that the rate at which the water is Withdrawn from the-contact chamber will be approx mately that at which water at ordinary temperature was admitted thereto.

When examination of the water leaving the bottom of the apparatus shows that such water no longer contains an appreciable quantity of foreign matter, either in suspension, or in solution, valve 31 is closed, to shut off the inflow of water to the chamber, and

' the contents of the latter are permitted to drain off until the chamber is entirely emptied. When the water has been entirely drained from the chamber, the pro cess is completed by passing heated air through the chamber from the top at a speed such that the contact masses are not disarranged, until they are thoroughly dry, and, preferably,

thereby raising the temperature of the chamber to that usual in contact operation, approximately 450 C. I have notthought it necessary to illustrate apparatus by means I of which this drying and heating operation may be carried out, since a similar operation is commonly employed in various arts, and different forms and-arrangements of apparatus are equally 'well adapted therefor.

Various changes may be made in my process and apparatus without departing from the spirit of my invention as specified in the appended claims.

I claim 1. A process for removing foreign sub stances from contact material mounted on fibrous material, which comprises washing said contact material with, water without disarranging such material.

2. A process for removing foreign matter I from contact substances mounted on fibrous material, which comprises introducing water into a receptacle containing the contact substance, at a place below such contact substance, until said substance is submerged, shutting off said water supply, introducing water into the receptacle above the contact substance, and discharging the water from the receptacle below the contact substance,

arranging the contact same rate at which it enters the receptacle stance, while at the same time permitting the operation being carried out without dissubstance or its car rler.

3. A process for removing foreign matter from contact substances mounted on fibrous material, which comprises introducing water into a receptacle containing the contact substance, at a place below said contact substance, until the receptacle is full, shutting ofl said water supply, introducing water into the receptacle above the contact sub-, stance, and at the same time permitting the water to discharge from the receptacle below the contact substance at substantially the above the'contact substance, the operation being carried out without disarranging the contact substance or its carrier.

4. A process for removing foreign matter from contact substances mounted on fibrous material, which comprises introducing Water into a receptacle containing the contact substance, at a place below said contact substance, until the rece tacle is full, shutting off said water supp y, introducing water into the receptacle above the contact sub stance, while at the same time permitting the water to discharge from the receptacle below the contact substance at substantially the same rate at which-it enters the recepta-- cle above the contact substance, shutting ofi the water supply from above, andpermitting all of the water to drain from the receptacle, the operation being carried out without disarranging the contact'substance or its carrier. v

5. A process for removing foreign matter from contact substances mounted onfibrous stance, until the receptacle is full, shutting ofl' said water supply, introducing water into the receptacle above the contact subthe Water to discharge from the receptacle below the contact substance at substantially the same rate at which it enters the recep- I tacle above the contact substance, shutting off the water supplyfrom above and permitting all of. the water to drainfrom the receptacle, and removing the remaining free moisture from the contact substance by ad mitting heated air to the receptacle above the contact substance, the operation being carried out without disarranging the contact substance or its carrier. i .7

- 6. A process for removing foreign matter from contact substances mounted on fibrous material, which comprises introducing water 12 5 into a receptacle containing the contact 'sub stance, at a place below. said contact substance, shutting off said water supply when the receptacle is full, introducin warmer water into the receptacle above t e contact substance after-the receptacle has been filled with the cooler Water, and at the same time permitting water to discharge from the receptacle below thecontact substance at substantially the same rate at which the warmer water is introduced, shutting oi]? the supply of warmer water, and permitting'the water contents of the receptacle to discharge therefrom below the contact material, the operation being carried out without disarranging 10 the contact substance or its carrier.

In testimony whereof l have hereunto set m hand. y THOMAS LYNTON BRIGGS. 

